<?php
/**
* @version $Id$
* @package utf8
* @subpackage strings
*/

//---------------------------------------------------------------
/**
* UTF-8 aware alternative to ord
* Returns the unicode ordinal for a character
* @param string UTF-8 encoded character
* @return int unicode ordinal for the character
* @see http://www.php.net/ord
* @see http://www.php.net/manual/en/function.ord.php#46267
*/
function utf8_ord($chr) {

	$ord0 = ord($chr);

	if ( $ord0 >= 0 && $ord0 <= 127 ) {
		return $ord0;
	}

	if ( !isset($chr{1}) ) {
		trigger_error('Short sequence - at least 2 bytes expected, only 1 seen');
		return FALSE;
	}

	$ord1 = ord($chr{1});
	if ( $ord0 >= 192 && $ord0 <= 223 ) {
		return ( $ord0 - 192 ) * 64
			+ ( $ord1 - 128 );
	}

	if ( !isset($chr{2}) ) {
		trigger_error('Short sequence - at least 3 bytes expected, only 2 seen');
		return FALSE;
	}
	$ord2 = ord($chr{2});
	if ( $ord0 >= 224 && $ord0 <= 239 ) {
		return ($ord0-224)*4096
			+ ($ord1-128)*64
				+ ($ord2-128);
	}

	if ( !isset($chr{3}) ) {
		trigger_error('Short sequence - at least 4 bytes expected, only 3 seen');
		return FALSE;
	}
	$ord3 = ord($chr{3});
	if ($ord0>=240 && $ord0<=247) {
		return ($ord0-240)*262144
			+ ($ord1-128)*4096
				+ ($ord2-128)*64
					+ ($ord3-128);

	}

	if ( !isset($chr{4}) ) {
		trigger_error('Short sequence - at least 5 bytes expected, only 4 seen');
		return FALSE;
	}
	$ord4 = ord($chr{4});
	if ($ord0>=248 && $ord0<=251) {
		return ($ord0-248)*16777216
			+ ($ord1-128)*262144
				+ ($ord2-128)*4096
					+ ($ord3-128)*64
						+ ($ord4-128);
	}

	if ( !isset($chr{5}) ) {
		trigger_error('Short sequence - at least 6 bytes expected, only 5 seen');
		return FALSE;
	}
	if ($ord0>=252 && $ord0<=253) {
		return ($ord0-252) * 1073741824
			+ ($ord1-128)*16777216
				+ ($ord2-128)*262144
					+ ($ord3-128)*4096
						+ ($ord4-128)*64
							+ (ord($chr{5})-128);
	}

	if ( $ord0 >= 254 && $ord0 <= 255 ) {
		trigger_error('Invalid UTF-8 with surrogate ordinal '.$ord0);
		return FALSE;
	}

}
